This prompted Len Nichols, director of health policy at the New America Foundation -- who says he is not affiliated with the Clinton campaign -- to call the mailer offensive, going so far as to play the Nazi card.

"It is outrageous as having Nazis march through Skokie, Illinois, or some other things we could think of probably if I had more time and my heart was beating less quickly," he said.

Clinton campaign senior adviser Howard Wolfson said on the call: “I heard someone make a reference to a march in Skokie in comparison to the photograph in the mailer which is not a comparison that we would make. And everyone on the call is obviously very passionate about this issue, and rightfully so, but that is not a comparison that we would make.”

In one picture in the Obama mailer a couple sits at a breakfast table talking about the issue, evoking the series of highly effective TV ads in the 90's that helped kill off Hillary Clinton's first failed effort to achieve health care reform.

Among the questions the mailer raises are the penalties Clinton would impose on those who fail to purchase insurance under her plan.

Clinton has dodged repeated questions to clarify what penalties she would impose. Today, on the call, campaign officials refused to be specific, saying only that as president she would decide the penalties "in consultation with Congress."

Under a similar mandatory plan in Massachusetts, the penalty for failing to buy health insurance are more than $200 in the first year rising to more than $1,000 in the second.

Obama's plan -- which is similar to Clinton's in many other respects -- would not require health insurance for adults but would aim instead to cover more people by reducing costs. He does require mandates when it comes to providing health insurance for children.

Clinton says Obama's plan would leave some 15 million uninsured, a figure he disputes.

It is, however, one thing to have a rational discussion - as the two candidates did last night.